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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 | // SPDX-License-Identifier: GPL-2.0-or-later /* CacheFiles extended attribute management * * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) */ #include <linux/module.h> #include <linux/sched.h> #include <linux/file.h> #include <linux/fs.h> #include <linux/fsnotify.h> #include <linux/quotaops.h> #include <linux/xattr.h> #include <linux/slab.h> #include "internal.h" static const char cachefiles_xattr_cache[] = XATTR_USER_PREFIX "CacheFiles.cache"; /* * check the type label on an object * - done using xattrs */ int cachefiles_check_object_type(struct cachefiles_object *object) { struct dentry *dentry = object->dentry; char type[3], xtype[3]; int ret; ASSERT(dentry); ASSERT(d_backing_inode(dentry)); if (!object->fscache.cookie) strcpy(type, "C3"); else snprintf(type, 3, "%02x", object->fscache.cookie->def->type); _enter("%p{%s}", object, type); /* attempt to install a type label directly */ ret = vfs_setxattr(&init_user_ns, dentry, cachefiles_xattr_cache, type, 2, XATTR_CREATE); if (ret == 0) { _debug("SET"); /* we succeeded */ goto error; } if (ret != -EEXIST) { pr_err("Can't set xattr on %pd [%lu] (err %d)\n", dentry, d_backing_inode(dentry)->i_ino, -ret); goto error; } /* read the current type label */ ret = vfs_getxattr(&init_user_ns, dentry, cachefiles_xattr_cache, xtype, 3); if (ret < 0) { if (ret == -ERANGE) goto bad_type_length; pr_err("Can't read xattr on %pd [%lu] (err %d)\n", dentry, d_backing_inode(dentry)->i_ino, -ret); goto error; } /* check the type is what we're expecting */ if (ret != 2) goto bad_type_length; if (xtype[0] != type[0] || xtype[1] != type[1]) goto bad_type; ret = 0; error: _leave(" = %d", ret); return ret; bad_type_length: pr_err("Cache object %lu type xattr length incorrect\n", d_backing_inode(dentry)->i_ino); ret = -EIO; goto error; bad_type: xtype[2] = 0; pr_err("Cache object %pd [%lu] type %s not %s\n", dentry, d_backing_inode(dentry)->i_ino, xtype, type); ret = -EIO; goto error; } /* * set the state xattr on a cache file */ int cachefiles_set_object_xattr(struct cachefiles_object *object, struct cachefiles_xattr *auxdata) { struct dentry *dentry = object->dentry; int ret; ASSERT(dentry); _enter("%p,#%d", object, auxdata->len); /* attempt to install the cache metadata directly */ _debug("SET #%u", auxdata->len); clear_bit(FSCACHE_COOKIE_AUX_UPDATED, &object->fscache.cookie->flags); ret = vfs_setxattr(&init_user_ns, dentry, cachefiles_xattr_cache, &auxdata->type, auxdata->len, XATTR_CREATE); if (ret < 0 && ret != -ENOMEM) cachefiles_io_error_obj( object, "Failed to set xattr with error %d", ret); _leave(" = %d", ret); return ret; } /* * update the state xattr on a cache file */ int cachefiles_update_object_xattr(struct cachefiles_object *object, struct cachefiles_xattr *auxdata) { struct dentry *dentry = object->dentry; int ret; if (!dentry) return -ESTALE; _enter("%p,#%d", object, auxdata->len); /* attempt to install the cache metadata directly */ _debug("SET #%u", auxdata->len); clear_bit(FSCACHE_COOKIE_AUX_UPDATED, &object->fscache.cookie->flags); ret = vfs_setxattr(&init_user_ns, dentry, cachefiles_xattr_cache, &auxdata->type, auxdata->len, XATTR_REPLACE); if (ret < 0 && ret != -ENOMEM) cachefiles_io_error_obj( object, "Failed to update xattr with error %d", ret); _leave(" = %d", ret); return ret; } /* * check the consistency between the backing cache and the FS-Cache cookie */ int cachefiles_check_auxdata(struct cachefiles_object *object) { struct cachefiles_xattr *auxbuf; enum fscache_checkaux validity; struct dentry *dentry = object->dentry; ssize_t xlen; int ret; ASSERT(dentry); ASSERT(d_backing_inode(dentry)); ASSERT(object->fscache.cookie->def->check_aux); auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, GFP_KERNEL); if (!auxbuf) return -ENOMEM; xlen = vfs_getxattr(&init_user_ns, dentry, cachefiles_xattr_cache, &auxbuf->type, 512 + 1); ret = -ESTALE; if (xlen < 1 || auxbuf->type != object->fscache.cookie->def->type) goto error; xlen--; validity = fscache_check_aux(&object->fscache, &auxbuf->data, xlen, i_size_read(d_backing_inode(dentry))); if (validity != FSCACHE_CHECKAUX_OKAY) goto error; ret = 0; error: kfree(auxbuf); return ret; } /* * check the state xattr on a cache file * - return -ESTALE if the object should be deleted */ int cachefiles_check_object_xattr(struct cachefiles_object *object, struct cachefiles_xattr *auxdata) { struct cachefiles_xattr *auxbuf; struct dentry *dentry = object->dentry; int ret; _enter("%p,#%d", object, auxdata->len); ASSERT(dentry); ASSERT(d_backing_inode(dentry)); auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, cachefiles_gfp); if (!auxbuf) { _leave(" = -ENOMEM"); return -ENOMEM; } /* read the current type label */ ret = vfs_getxattr(&init_user_ns, dentry, cachefiles_xattr_cache, &auxbuf->type, 512 + 1); if (ret < 0) { if (ret == -ENODATA) goto stale; /* no attribute - power went off * mid-cull? */ if (ret == -ERANGE) goto bad_type_length; cachefiles_io_error_obj(object, "Can't read xattr on %lu (err %d)", d_backing_inode(dentry)->i_ino, -ret); goto error; } /* check the on-disk object */ if (ret < 1) goto bad_type_length; if (auxbuf->type != auxdata->type) goto stale; auxbuf->len = ret; /* consult the netfs */ if (object->fscache.cookie->def->check_aux) { enum fscache_checkaux result; unsigned int dlen; dlen = auxbuf->len - 1; _debug("checkaux %s #%u", object->fscache.cookie->def->name, dlen); result = fscache_check_aux(&object->fscache, &auxbuf->data, dlen, i_size_read(d_backing_inode(dentry))); switch (result) { /* entry okay as is */ case FSCACHE_CHECKAUX_OKAY: goto okay; /* entry requires update */ case FSCACHE_CHECKAUX_NEEDS_UPDATE: break; /* entry requires deletion */ case FSCACHE_CHECKAUX_OBSOLETE: goto stale; default: BUG(); } /* update the current label */ ret = vfs_setxattr(&init_user_ns, dentry, cachefiles_xattr_cache, &auxdata->type, auxdata->len, XATTR_REPLACE); if (ret < 0) { cachefiles_io_error_obj(object, "Can't update xattr on %lu" " (error %d)", d_backing_inode(dentry)->i_ino, -ret); goto error; } } okay: ret = 0; error: kfree(auxbuf); _leave(" = %d", ret); return ret; bad_type_length: pr_err("Cache object %lu xattr length incorrect\n", d_backing_inode(dentry)->i_ino); ret = -EIO; goto error; stale: ret = -ESTALE; goto error; } /* * remove the object's xattr to mark it stale */ int cachefiles_remove_object_xattr(struct cachefiles_cache *cache, struct dentry *dentry) { int ret; ret = vfs_removexattr(&init_user_ns, dentry, cachefiles_xattr_cache); if (ret < 0) { if (ret == -ENOENT || ret == -ENODATA) ret = 0; else if (ret != -ENOMEM) cachefiles_io_error(cache, "Can't remove xattr from %lu" " (error %d)", d_backing_inode(dentry)->i_ino, -ret); } _leave(" = %d", ret); return ret; } |